“Exit Enclosure” was deleted from the definitions, but not from the code. Stairways can be many things within the MOE system. A stairway can be either an “exit access” element or an “exit” element. There are also enclosed and open stairways. The changes were a comprehensive revamping of the code to clarify the use of stairways within a means of egress systems. The following are the main concepts for the changes:

■ All stairways within a building are elements of the MOE system.
■ Exit stairways are required to be enclosed.
■ Unenclosed stairways are not “exits.”
■ Stairways that are permitted to be open are “exit access stairways” and must comply
with one of the ten exceptions in Section 1009.3 for an open stairway.

Travel Distance – An open stairway that is part of an exit access may have the distance traveled over the stairs as part of the overall exit travel. In other words, a second story of a building may have one enclosed exit stair and one open stairway to the first floor and comply with the code, as long as the maximum travel distance to an exit (either an enclosed stairway or exterior exit doorway) is complied with from all points on the second floor. This may include travel down the open stairways to an exit.

Single Exit – This takes us to another confusing part of the code. When can you have a single exit from a story or space? The basic premise of the code in Section 1021 is that each story is required to have a minimum of access to two exits. However there are six conditions outlined in Section 1021.2 that permits a single exit:

1. Maximum permitted travel distance is not exceeded.
2. Space(s) have access to an exterior door or exit.
3. R-3/dwellings complying with Table 1021.2(1)
4. Mechanical parking garages
5. R-3/dwelling and R-4/Congregate Residences complying with Table 1021.2(1)
6. Individual dwelling units complying with the requirements for a single exit in Section 1015.1 and the exit is directly to the exterior.

Read Section 1021.2 for all detailed requirements associated with a single exit. The primary premise is low occupant load and short travel distance to a point of safety.

Note: Section 1021 of the CBC is different from what is found in the 2012 IBC. The IBC rewrote this complete section and the State decided it did not fit their needs regarding single exit concepts. In the CBC there is a Table 1021.3(1), which is not found in the IBC. This table addresses the minimum number of exits for a giving occupant load. The IBC uses text to address multiple exits. So, if you are familiar with
the IBC’s version, make note that what is in the CBC is different and may be applied/interpreted differently. This goes for those who normally use the CBC and do work out of the State where only the IBC applies.

Erick Mikiten, AIA LEED-AP Mikiten Architecture

Erick Says:

It’s worth noting that the word “access” in the code term “access to exits” means availability of exits, not usability by people with disabilities. Keep these separate in your mind as you’re using the CBC.

You’ll also come across “Accessible Means of Egress” (a continuous emergency egress path from an accessible spot in a building) and “Accessible Route” (the creation of a continuous path connecting all the accessible elements of a site, building or facility together; it’s about daily usability, not emergencies).

When determining the level of accessibility required in your egress system, Section 1007 requires all accessible spaces to have at least one Accessible Means of Egress. It details the elements of the egress system, including the requirements that allow stairways (ironically) and elevators to be used. There are also exceptions for existing buildings, mezzanines and assembly areas.

But remember-the code only gives us minimums. If you can make more exits accessible than required, such as using a ramp rather than a stair, you will create a building that more people can use at all times, and that will allow everyone to exit more smoothly and safely.

Recent Posts

Twitter

About AIA East Bay

AIA East Bay, an architectural community, supports our membership in exemplary practice and professional growth.

Our many programs include education for San Francisco Bay Area architects and outreach to the community on vital topics such as earthquake safety, fire safety, sustainable design, and those architect-related issues that focus on how the Bay Area community benefits from well-informed design and development.